.. _vibration_reduction:

=====================
 Vibration Reduction
=====================

Camera vibrations caused by mirror movement can reduce sharpness.  The effect is
the more noticeable the longer the exposure time becomes.  To reduce these
vibrations use live view or exposure delay mode.

Single-lens reflex (SLR) cameras use a mirror to deflect the light into the
viewfinder.  This mirror obscures the sensor and therefore must be lifted before
the camera can take an exposure.  The lifting of the mirror causes the camera to
vibrate slightly, even if the camera is mounted on a tripod\ [#]_.


Live View
=========

In live view mode the camera does not use the viewfinder at all and the mirror
will be locked in the *up* position.  This mode, when implemented correctly\
[#]_, can greatly reduce camera vibrations.

Another advantage of live view ist that you can attach a HDMI monitor to your
camera and preview the picture on a big screen.


Exposure Delay Mode
===================

Use this mode is live view is not available or broken.  This mode waits 1 second
after lifting the mirror and before actually taking the picture.  Most of the
vibration has damped by then.

Exposure delay mode does incur a speed penalty but this penalty is less than one
second per exposure because you must subtract the time it takes the camera to
write the picture to the memory card.


Mirrorless Cameras
==================

Mirrorless Interchangeable-Lens Cameras (MILC) do not have a mirror and thus are
for RTI imaging a suitable alternative to the more common (as of 2018) SLR type.
The lenses for MILC cameras are not compatible with SLR type lenses and being
comparatively new the choice of lenses is more limited (but there are adapters).


Footnotes
=========

.. [#] The shutter movement also causes the camera to vibrate, but the shutter
       is much lighter than the mirror assembly.  The shutter is essential to
       camera operation and thus cannot be avoided.

.. [#] Live view on the Nikon D700 is useless as it does not keep the mirror up
       between shots.